Agricultural chemicals, such as herbicides, insecticides, and fungicides are typically combined with carriers and adjuvants to obtain a formulated product before sale to the ultimate user. The adjuvants and carriers employed add to the cost and, in some cases, make the products less desirable environmentally. On the other had, these ingredients often contribute positively to the efficacy of the formulated product. The organic solvents, especially hydrocarbon solvents, typically found in formulated agricultural products are examples of carriers that have these characteristics. The preparation of formulated agricultural products that contain very little or no organic solvent, and, especially, no petroleum hydrocarbon or chlorinated hydrocarbon solvents, but that are at least as effective as formulated products that do, is a desirable objective.
Fluroxypyr, which is ((4-amino-3,5-dichloro-6-fluoro-2-pyridinyl)oxy)acetic acid, is a commercially available herbicide that is presently sold as the 1-methylheptyl ester in the form of an emulsifiable concentrate formulation containing 180 grams of acid equivalent per liter of formulation. Emulsifiable concentrate formulations containing higher levels of this ester and common solvents were found to be unsuitable due to solubility limitations. U.S. Pat. No. 4,108,629 proposes that emulsifiable concentrate formulations containing from about 2 to about 50 percent of fluroxypyr esters can be prepared, but only discloses such formulations containing up to about 25 percent.
Wettable powder and water dispersible granule formulations containing fluroxypyr in the form of the 1-methyl-heptyl ester have not been commercialized because they are not as effective as liquid formulations. The efficacy of such formulations can be improved by the addition of a low-volatile organic solvent, but this is not desirable because, in addition to the previously mentioned disadvantages of such solvents, they reduce the amount of fluroxypyr ester that the product can contain and still maintain acceptable physical properties.